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Warm days in May

May 25, 2012

Warm days in May

May 18th (last Friday) brought a warm day to the state with many
observers reporting daytime highs in the 90s F, the warmest May 18th
since 1998. Madison topped the list with a record-setting 97 degrees F.
Other climate stations setting new temperature records on May 18th
included: 95 degrees F at Browns Valley; 93 degrees F at Moorhead; 92
degrees F at Park Rapids; and 94 degrees F at Wheaton.

May 22-23
brought more record high temperatures to the region just ahead of heavy
thunderstorms. Fargo, ND set a record on the 22nd with 93 degrees F.
Then more record highs were set on Wednesday, May 23rd, including 92
degrees F at Amboy, 89 degrees F at MSP and Austin, and 87 degrees F at
Lakefield (tied 2010). Strong south winds ushered in very moist air
across the state on the 23rd. Between 8:00 pm and 9:00 pm the dewpoint
at MSP Airport rose from 51 degrees F to a sticky 65 degrees F.

Heavy rains on May 23-24

Strong winds, hail, and very heavy thunderstorm rainfall visited the
state over May 23-24 this week. Wind gusts to 75 mph were reported from
New Ulm, and 71 mph at New Prague. Some western and southern counties
reported half to one inch diameter hail as well.

The real story
was in the number of reports of heavy rainfall, with many observers
reporting 2 to over 5 inches. Those reporting record-setting rainfalls
included: 4.77 inches at Buffalo; 3.46 inches at Gaylord; 3.81 inches at
Glencoe; 2.58 inches at MSP Airport; 2.89 inches at Two Harbors; 3.64
inches at Waconia; 3.01 inches at Andover; 3.50 inches at Elk River;
2.12 inches at Floodwood; 2.87 inches at Forest Lake; 2.88 inches at
New Ulm; 2.76 inches at Lakefield; 2.90 inches at Windom; and 3.50
inches at St Francis. Many other observers reported record-setting
amounts of rainfall as well, adding to already above normal amounts for
May. It was one of the heaviest doses of 24 hour rainfall ever measured
in the state during the month of May, the amount of 4.77 inches at
Buffalo (Wright County) breaking the all-time state record rainfall for
May 24th (formerly 3.60 at Long Prairie in 1939).

Monthly total
rainfall for May now exceeds 7 inches at many locations around the state
including: Buffalo, Chaska, MSP, Hastings, Hutchinson, New Ulm, Milaca,
Mora, Springfield, Jordan, Andover, Forest Lake, Chanhassen, Lakefield,
Pipestone, Windom, Lamberton, and Rockford. The 8.18 inches at MSP
airport marks the 2nd wettest all-time May (record is 10.33 inches in
1906) and wettest since 1965. The National Weather Service Forecast
Office in Chanhassen has reported 9.22 inches of rainfall so far in May.
This total is getting close to the state record rainfall for May of
11.70 inches at Winnebago back in 1908. So, with more rainfall forecast
for the last week of the month, the record amount for May may be
surpassed.

With one week to go in the month, May of 2012 on a
statewide basis already ranks among the ten wettest dozen in state
history. It is likely that these rainfall totals will be added to by
the end of the month.

Weekly Weather Potpourri

The National Oceanic and Atmospheric Administration is predicting a
near-normal Atlantic Hurricane Season given the present atmospheric and
oceanic measurements and patterns. This means 9-15 named storms with 4
to 8 of those strong enough to reach hurricane status. Further, 1 to 3
of these storms may reach major hurricane status (category 3 or higher).
You can read more here.

Two major storms were operating in tropical waters this week.
Typhoon Sanvu was spinning south of Japan in the western Pacific Ocean.
It was producing wave heights over 30 feet with winds up to 90 mph and
higher gusts. Sanvu is expected to weaken over the weekend as it pulls
away from Japan to the east. It is not expected to make landfall.
Hurricane Bud, the second named storm of the hurricane season, was off
the west coast of Mexico in the Eastern Pacific Ocean with winds close
to 110 mph and sea waves near 30 feet. It is expected to weaken towards
the weekend, before making landfall. Bud will likely bring 6 to 10
inch rains to some coastal communities in Mexico.

Dr. Rick
Knabb, former hurricane expert with The Weather Channel, was named last
week as the new Director of the NOAA National Hurricane Center in Miami,
FL. He replaces the retiring director Bill Read. Dr. Knabb returns to
NOAA where he previously served as Deputy Director of the Central
Pacific Hurricane Center in Hawaii. You can read more about him here.

The National Weather Service Forecast Office in Indianapolis has
provided a climatology for the Indianapolis 500 Motor Race which takes
place this Sunday (May 27th). The warmest race day was in 1937 with 92
degrees F, while the coldest race day was 1992 with just 58 degrees F.
You can find more detail about historical weather for the race here.

The National Weather Service has declared Friday, 25 May 2012, as Heat
Awareness Day across the nation. For more information, including safety
measures for children in motor vehicles and too much outdoor exposure
when Heat Index Values are over 100 degrees you can consult the National
Weather Service's webpage here.

MPR listener question

Two listeners wrote with a question about winds: High winds have
limited the use of herbicides so far this crop season. Have wind speeds
been higher than usual this month and for the spring season so far?

Answer:
As a reminder to readers, at most climate stations in Minnesota April
and May are two of the windiest months of the year based on historical
mean values of wind speed. Using the MSP Airport measurements for frame
of reference, mean wind speeds during March, April, and May have been
near average or slightly below average this year. However, that is
deceiving relative to the frequency of high wind gusts, which have been
highly unusual in frequency. Listed below are the number of days with
wind gusts greater than 30 mph, 40 mph, and 50 mph for the months of
March, April, and May (so far) from MSP International Airport, along
with the peak wind gust speed in parentheses:

March: 9 days with wind gusts of 30 mph or greater; 4 days with wind gusts of 40 mph or greater (peak 47 mph)
April: 14 days with wind gusts of 30 mph or greater; 2 days with wind gusts of 40 mph or greater (peak 44 mph)
May:
16 days with wind gusts of 30 mph or greater; 6 days with wind gusts of
40 mph; 2 days with wind gusts of 50 mph (peak 58 mph)

Normally
these months bring wind gusts greater than 30 mph on only 5 or 6 days.
Further very strong wind gusts have been reported this May at other
locations around the state, including: 58 mph at Redwood Falls; 54 mph
at Duluth; 46 mph at St Cloud and Rochester; and 45 mph at Mankato.

Twin Cities Almanac for May 25th

The average MSP high temperature for this date is 72 degrees F (plus or
minus 9 degrees F standard deviation), while the average low is 51
degrees F (plus or minus 8 degrees F standard deviation).

Average dew point for May 25th is 47 degrees F, with a maximum of 72 degrees F in 1916 and a minimum of 23 degrees F in 1934.

All-time state records for May 25th

The state record high temperature for this date is 100 degrees F at
Luverne (Rock County) in 1967; the state record low temperature for this
date is 19 degrees F at Tower (St Louis County) in 1983. State record
precipitation for this date is 4.32 inches at St James (Watonwan County)
in 1953; and state record snowfall for this date is 4.0 inches at
Baudette (Lake of the Woods County) in 1970.

May
25-26, 1967 brought a heat wave to southern Minnesota as 24 communities
reported afternoon highs in the 90s F. A strong cold front dropped
temperatures into the 60s and 70s F on May 27th.

May 25, 1970
brought a late spring snow storm to north-central Minnesota where
Baudette reported 4 inches, Big Falls reported 2.0 inches, and
International Falls received 0.3 inches. The snow was followed by cold
Canadian high pressure keeping daytime temperatures down into the 40s
and 50s F over May 25-28.

May 25, 1983 brought a late spring hard
freeze to northern counties as over 30 communities reported morning lows
in the 20s F. In the Red River Valley some crops had to be replanted.

Word of the Week: ACE

This acronym stands for Accumulated Cyclone Energy (ACE) index which is
used by the United Kingdom Meteorological Office to estimate the
seasonal number of tropical storms in the North Atlantic. Using the ACE
index the UK Met Office predicts 7-13 named storms for the 2012 season
(June through November), with a most likely value of 10. This is
slightly less than the seasonal average of 12.

Outlook

An unsettled weekend weather wise with mostly cloudy skies and roller
coaster temperature pattern. Showers and thunderstorms are likely each
day, with a warm and sultry day on Sunday as temperatures reach the 90s F
in some locations. Cooler temperatures by Monday and cooler yet on
Tuesday but drier. Chances for showers return on Wednesday and Thursday
next week to conclude the wet May.